1. Field of the Invention
Embodiments of the present invention generally relate to techniques for performing seismic imaging.
2. Description of the Related Art
Isotropic velocity analysis followed by isotropic depth migration may result in large errors in seismic depth images where the earth is anisotropic. For example, in the Gulf of Mexico, it may not be unusual to observe mis-ties of 1,000 ft, or more, at depths below 10,000 ft. As a consequence, isotropic images may be frequently adjusted to tie more accurate data at wells. A common approach may use the isotropic velocities to convert the image to time, followed by conversion back to depth with a calibration velocity. A problem may be how best to estimate the calibration velocity; in particular, how to deduce the calibration velocity far from the nearest well.
Because of the sparsity of well locations, calibrations may be ambiguous. A clear pitfall to avoid may be the creation of a prospect that is not in the isotropic image and is not supported by the wells.